As is well known in the hot melt adhesive material dispensing art or industry, a typical hot melt adhesive material dispensing system comprises three primary components, an applicator head which comprises a hot melt adhesive material dispensing nozzle for dispensing a predetermined amount of the hot melt adhesive material, in a predetermined pattern, onto a substrate, an adhesive supply unit (ASU) which supplies the hot melt adhesive material to the applicator head, and a hot melt adhesive material hose assembly by means of which the hot melt adhesive material is conducted from the hot melt adhesive supply unit (ASU) to the applicator head. The hot melt adhesive material hose assembly conventionally comprises a tubular member which may be fabricated, for example, from TEFLON®, a stainless steel wire braid-type woven layer disposed therearound, and a pair of end fittings disposed upon opposite ends of the tubular member so as to respectively connect the opposite ends of the hot melt adhesive material hose assembly to the adhesive supply unit and to the applicator head. The tubular member, the end fittings, and the stainless steel wire braid-type woven layer together define the hot melt adhesive material hose core, and the hot melt adhesive material hose core is encased within multiple layers of wrapped tape. Furthermore, a heater circuit or wire is operatively associated with the hot melt adhesive material hose assembly, by being wrapped around the hot melt adhesive material hose core and disposed beneath one or more of the aforenoted layers of tape, in order to maintain the hot melt adhesive material, being conducted through the hot melt adhesive material hose assembly, at a predetermined temperature level such that the hot melt adhesive material will have or exhibit the proper viscosity properties when the hot melt adhesive material is to be dispensed from the dispensing nozzles of the applicator head.
Still yet further, it is also noted that the adhesive supply unit (ASU) comprises various electrical components, such as, for example, hot melt adhesive material supply pumps for supplying predetermined amounts of the hot melt adhesive material to the hot melt adhesive material hose assembly and ultimately to the applicator head, hot melt adhesive material supply valving for controlling the actual supply of the hot melt adhesive material into, through, or out from the adhesive supply unit (ASU), and the like. In a similar manner, it is noted that the applicator head also comprises various electrical components, such as, for example, solenoid-controlled mechanisms operatively associated with the hot melt adhesive material dispensing nozzle valving structure, valving structure utilized for controlling the routing or flow of control air streams, and the like. Accordingly, opposite end portions of the hot melt adhesive material hose assembly are respectively provided with electrical connectors which are not only adapted to be electrically connected to mating electrical connector structures fixedly mounted upon the hot melt adhesive supply unit (ASU) and the applicator head, but in addition, are adapted to terminate coaxial power cable assemblies through which various electrical wires, for providing electrical power and electrical connections to the aforenoted electrical components of the hot melt adhesive supply unit (ASU) and the applicator head, are routed.
It can therefore be readily appreciated that in view of the multiplicity of electrical connections that need to be made and implemented, a multiplicity of electrical wires must be routed between the various electrical components housed within the adhesive supply unit (ASU) and the various electrical components housed within the applicator head, and since the hot melt adhesive material hose assembly is effectively the only means effectively interconnecting the adhesive supply unit (ASU) to the applicator head, the wires must be routed along the hot melt adhesive material hose assembly. Accordingly, not only does a multiplicity of electrical wires need to be routed between the adhesive supply unit (ASU) and the applicator head, and along the hot melt adhesive material hose assembly, and not only does a multiplicity of electrical connections need to be made upon both the adhesive supply unit (ASU) and applicator head ends of the system, but in addition, the multiplicity of electrical wires add considerable size, bulk, and weight to the hot melt adhesive material hose assembly. Still yet further, it is also known in the hot melt adhesive material art or industry that the adhesive supply unit (ASU) conventionally comprises a temperature controller which is adapted to control the energization of the heater circuit or wire incorporated within the hot melt adhesive material hose assembly and/or the heater element incorporated within the applicator head so as to maintain the temperature of the hot melt adhesive material, either within the hot melt adhesive material hose assembly or within the applicator head, at a predetermined set point or level in response temperature levels sensed by one or more temperature sensors which may comprise, for example, resistance temperature detectors (RTDs). It is noted, however, that the space which is available upon the adhesive supply unit (ASU) for accommodating one or more temperature controllers is somewhat limited, and accordingly, only a limited or pre-determined number of temperature controllers are in fact able to be accommodated upon the adhesive supply unit (ASU). Thus, in view of such limited amount of available space upon the adhesive supply unit (ASU), the number of applicator heads that may be serviced by means of a single adhesive supply unit (ASU) is correspondingly limited.
A need therefore exists in the art for a new and improved hot melt adhesive material dispensing system wherein not only can the number of electrical wires and electrical connections between the adhesive supply unit (ASU) and the applicator head be substantially reduced, but in addition, the temperature controllers can be respectively incorporated within the applicator heads such that a multiplicity of applicator heads can easily be serviced by means of a single adhesive supply unit (ASU).